php – pdo lastInsertId返回零(0)

所有查询执行成功,当我检查MySQL行中的表成功插入没有任何错误,但lastInsertId()返回0.为什么？

我的代码：

// queries executes successfully, but lastInsetId() returns 0
// the menus table has `id` column with primary auto_increment index
// why lastInsertId return 0 and doesn't return actual id?


$insertMenuQuery = " 
 SELECT @rght:=`rght`+2,@lft:=`rght`+1 FROM `menus` ORDER BY `rght` DESC limit 1; 
 INSERT INTO `menus`(`parent_id`, `title`, `options`, `lang`, `lft`, `rght`) 
      values 
  (:parent_id, :title, :options, :lang, @lft, @rght);";
     try {
           // menu sql query
           $dbSmt = $db->prepare($insertMenuQuery);

           // execute sql query
           $dbSmt->execute($arrayOfParameterOfMenu);
           // menu id
           $menuId = $db->lastInsertId();

           // return
           return $menuId;

     } catch (Exception $e) {
          throw new ForbiddenException('Database error.' . $e->getMessage());
     }

解决方法:

使用PDO_MySQL我们必须使用

$DB->setAttribute(PDO::ATTR_EMULATE_PREPARES,TRUE); // there are other ways to set attributes. this is one

这样我们就可以运行多个查询,例如：

$foo = $DB->prepare("SELECT * FROM var_lst;INSERT INTO var_lst (value) VALUES ('durjdn')");

但遗憾的是,这样做可以减少$DB返回正确的插入ID.您必须单独运行它们才能检索插入ID.这将返回正确的插入ID：

$DB->setAttribute(PDO::ATTR_EMULATE_PREPARES,TRUE);
$foo = $DB->prepare("INSERT INTO var_lst (value) VALUES ('durjdn')");
$foo->execute();
echo $DB->lastInsertId();

但这不会：

$DB->setAttribute(PDO::ATTR_EMULATE_PREPARES,TRUE);
$foo = $DB->prepare("SELECT * FROM var_lst;INSERT INTO var_lst (value) VALUES ('durjdn')");
$foo->execute();
echo $DB->lastInsertId();

这甚至不会运行两个查询：

$DB->setAttribute(PDO::ATTR_EMULATE_PREPARES,FALSE); // When false, prepare() returns an error
$foo = $DB->prepare("SELECT * FROM var_lst;INSERT INTO var_lst (value) VALUES ('durjdn')");
$foo->execute();
echo $DB->lastInsertId();

标签：php,mysql,pdo,lastinsertid
来源： https://codeday.me/bug/20190716/1477888.html